A package protects an enclosed object from a physical impact such as mechanical shock, vibrations, electrostatic charges, or acts as a barrier to chemical impact such as humidity, oxygen, or dust. Hence, a package enables temporary storage, safe transportation, display and handling of the object enclosed while the object enclosed can be removed without marks or signs of wear.
Especially within the semiconductor industry, where careful handling of the dies is crucial in order to minimize the yield loss, a microprocessor die needs to be removed from the package without damage. Microprocessors are block shaped devices typically made out of a solid semiconductor material in a batch type manufacturing process, where a wafer is singulated into individual dies. The singulated microprocessor die is usually transferred to a carrier tape, also referred to so as a bare die tape (BDT), for packaging after singulation and prior to inspection, shipment and assembly. Currently, this carrier tape type package is made out of a flat cuboid shaped material with a plurality of pockets formed into the carrier tape for the dies to sit in. After placing a die into the pocket of the carrier tape, a cover tape is attached to the carrier tape in order to seal the die in the pocket. The cover tape has a layer of heat activated adhesive (HAA) or a pressure activated adhesive (PAA). Both adhesion techniques require the entire cover tape surface area to be coated in the adhesive. When the cover tape seals the die in a carrier tape package, the pocket with the die is also exposed to the cover tape's adhesive. Since there is no alignment of the die in a carrier tape to the cover tape with existing toolsets, it is difficult to sufficiently seal the die in the carrier tape pocket. Conventional PPA techniques require an additional blocker layer applied to the faces of a semiconductor die in order to protect the die from the activation pressure. Due to the blocker layer, only the edges of the carrier tape may remain uncovered by the blocker layer, limiting the available cover tape sealing area to the reduced space around blocker layer.
Due to the limited possibility of die alignment in the carrier tape and the lack of adhesive application control with the cover tape, a sub-optimal sealing and die packaging is present. Especially the issues of dies sticking to the cover tape and gross die out of pocket (DOOP) translates to a yield loss as well as extensive waste of adhesive, when coating the entire cover tape surface area. In addition, the adhesive layer interferes with the manual and automated inspection of the die after packaging which leads to a high rejection rate.
There is a desire to improve the process of die packaging and die inspection.